Thrombin Generation.

The thrombin generation assay via the calibrated automated thrombography displays the concentration of thrombin in clotting plasma by monitoring the splitting of a fluorogenic substrate and comparing it to a constant known thrombin activity in a parallel non clotting sample (Hemker et al, 2003). In platelet poor plasma (PPP) the thrombin generation curve can be used as a test of function of coagulation  and is sensitive to all coagulation factor deficiencies (with the exception of factor XIII) (Al Dieri et al, 2002) and the effect of all anticoagulants including heparins of all types (Al Dieri et al, 2003).

This study will firstly try to show that the thrombin generation assay and in particular the endogenous thrombin potential is, as reported previously (Al Dieri et al, 2006; Al Dieri et al, 2004), sensitive to heparin at varying concentrations, i.e. it shows a dose response effect. Secondly it will correlate and compare the anti-FXa assay (a measurement of heparin concentration) with the endogenous thrombin potential (ETP) of thrombin generation in pregnant females who are taking a standard dose of LMWH (enoxaparin) of 1mg/kg twice daily. This project aims to show that the ETP may in future have a use as a measure of the control of heparin in pregnant women on high dose enoxaprine (1mg/Kg twice daily ) at risk of VTE, and would be in fact a better measurement than the anti-FXa assay a measurement of heparin concentration rather than function of Thrombotic potential.